Study on Seasonal Variation of Eucommiol in Eucommia ulmoides leaves

Objective:To observe the variety trend of eucommoil in Eucommia ulmoides leaves for determining the optimal harvest time of E.ulmoides leaves.Methods:The amounts of eucommoil in E.ulmoides leaves collected at different time were measured by HPLC.Results:Significant differences of eucommoil were observed among the different collecting time of E.ulmoides leaves.Conclusion:The eucommoil in E.ulmoides leaves is highest in mid-September(1.450%) and lowest in May(0.173%).The optimal harvest time is about mid-September.